September weather forecast
Calistoga, CA

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Vineyard and tree lines in a plantation in the Napa Valley in Calistoga, California
Vineyard and tree lines in a plantation in the Napa Valley in Calistoga, California

Weather in September

The first month of the autumn, September, is still a warm month in Calistoga, California, with an average temperature fluctuating between 54.5°F (12.5°C) and 84.4°F (29.1°C).

Temperature

As Calistoga welcomes September, the average high-temperature is noted at a moderately hot 84.4°F (29.1°C), closely aligning with the preceding month. September nights showcase a dramatic shift from daytime highs to an average temperature of 54.5°F (12.5°C).

Heat index

During September, the heat index is appraised at a hot 86°F (30°C). If one continues to be active during enduring exposure, it could result in fatigue and heat cramps.
In reference to the heat index, it's for places in shade and with a slight wind. The heat index might be elevated by 15 Fahrenheit (8 Celsius) degrees due to direct sun exposure.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. This effect tends to be personal, with the weather perception differing among individuals due to variations in body mass, height, and exertion. The sun, when shining directly, can have a significant impact on the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Children often overlook the necessity for resting and fluid replenishment. Thirst is a late sign of dehydration - thus, it is critical to stay hydrated, especially during extended periods of physical activities.

Humidity

With an average relative humidity of 53%, September is the least humid month.

Rainfall

In September, in Calistoga, the rain falls for 2.1 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. In Calistoga, during the entire year, the rain falls for 77 days and collects up to 17.05" (433mm) of precipitation.

Snowfall

January, March through December are months without snowfall in Calistoga.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:40 am and sunset at 7:39 pm. On the last day of September, sunrise is at 7:06 am and sunset at 6:54 pm PDT.

Sunshine

In Calistoga, the average sunshine in September is 11.1h.

UV index

In Calistoga, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for the ordinary person.
Note: In September, a regular UV index of 5 translates into these guidelines:
Undertake precautions - Obligation exists to protect against skin and eye damage. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days.
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Frequently asked questions

How hot does it get in Calistoga in September?

In September, in Calistoga, the average high-temperature is 84.4°F (29.1°C), and the average low-temperature is 54.5°F (12.5°C). In September, the average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is appraised at 86°F (30°C).

What is the least humid month in Calistoga?

September is the least humid month in Calistoga, California, with an average relative humidity of 53%.

What is the average humidity in September in Calistoga?

In September, the average relative humidity in Calistoga, California, is 53%.

How many days does it rain in September in Calistoga?

In Calistoga, in September, it is raining for 2.1 days, with typically 0.08" (2mm) of accumulated precipitation.

When it does not snow in Calistoga?

In Calistoga, snow does not fall in January, March through December.

How many hours of daylight does Calistoga have in September?

The average day length in September is 12h and 25min.

When is the sunrise / sunset in September in Calistoga?

On the first day of September in Calistoga, California, sunrise is at 6:40 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:06 am and sunset at 6:54 pm PDT.

How long on average sun shines in September in Calistoga?

The average sunshine duration in September is 11.1h.

How high is the UV index in September in Calistoga?

In Calistoga, California, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Calistoga, CA

Average temperature in September - Calistoga, CA
  • Average high temperature in September: 84.4°F

The warmest month (with the highest average high temperature) is August (87.8°F).
The month with the lowest average high temperature is December (54.7°F).

  • Average low temperature in September: 54.5°F

The month with the highest average low temperature is July (55.4°F).
The coldest month (with the lowest average low temperature) is December (39.4°F).

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Average pressure in September
Calistoga, CA

Average pressure in September - Calistoga, CA
  • Average pressure in September: 29.91"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.91"Hg).

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Average wind speed in September
Calistoga, CA

Average wind speed in September - Calistoga, CA
  • Average wind speed in September: 4.4mph

The windiest months (with the highest average wind speed) are April and May (5.7mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).

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Average humidity in September
Calistoga, CA

Average humidity in September - Calistoga, CA
  • Average humidity in September: 53%

The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is September (53%).

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Average rainfall in September
Calistoga, CA

Average rainfall in September - Calistoga, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (3.78").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
Calistoga, CA

Average rainfall days in September - Calistoga, CA
  • Average rainfall days in September: 2.1 days

The month with the highest number of rainy days is March (13.6 days).
The month with the least rainy days is August (0.8 days).

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Average snowfall in September
Calistoga, CA

Average snowfall in September - Calistoga, CA
  • Average snowfall in September: 0"

The month with the highest snowfall is February (0.04").
The months with the least snowfall are January, March, April, May, June, July, August, September, October, November and December (0").

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Average snowfall days in September
Calistoga, CA

Average snowfall days in September - Calistoga, CA
  • Average snowfall days in September: 0 days

The months with the highest number of snowfall days are February and March (0.1 days).
The months with the least snowfall days are January, April, May, June, July, August, September, October, November and December (0 days).

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Average daylight in September /
Average sunshine in September
Calistoga, CA

Average daylight in September / Average sunshine in September - Calistoga, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 11h and 1min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).

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Average sunshine days in September
Calistoga, CA

Average sunshine days in September - Calistoga, CA
  • Average sunshine days in September: 27.4 days

The month with the most sunshine days is July (29.8 days).
The month with the least sunshine days is March (15.8 days).

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Average UV index in September
Calistoga, CA

Average UV index in September - Calistoga, CA
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 2).

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Average cloud cover in September
Calistoga, CA

Average cloud cover in September - Calistoga, CA
  • Average cloud cover in September: 9

The month with the most cloud cover is March (Cloud cover 42).
The month with the least cloud cover is July (Cloud cover 5).

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Average visibility in September
Calistoga, CA

Average visibility in September - Calistoga, CA
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is March (5mi).

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Calistoga, California, USA

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